When we sleep, we may be mentally at rest (if we’re lucky). But our bodies—complexions included–use snooze time to repair, process and recover from the day that came before.

“Sleep is vitally important to good health, and lack of sleep affects the skin more than it does other organs of our body,” according to Dr. Jerome Z. Litt, a dermatologist in Cleveland, Ohio.

To understand why sleep loss has such an impact on how we look, it’s important to understand the benefits of a good night’s rest. “As people sleep, skin rejuvenation takes place and the cells undergo a process of repair,” Litt says. Levels of the hormone cortisol are at their lowest at night, which means sleep acts as a natural anti-inflammatory for the skin. Our circulation, on the other hand, increases, so more nutrients and oxygen—which are needed in order for the skin to repair itself—are reaching the skin while we sleep.

Of course, getting enough beauty rest isn’t always easy. Here’s how you can ensure that the sleep you do get will give you the biggest beauty-boosting benefits.

Shoot for at least seven hours of sleep. Eight hours would be optimal, according to Litt, but at least seven will give your skin the time it needs to get through its entire restorative process.

Wash your face before bed. Removing makeup, dirt and traces of pollution that accumulate on your skin throughout the day can keep your pores clear and protects against product buildup that can thwart the repair process. The products you apply during the day tend to break down over time and separate into ingredients that on their own can be harmful to your skin. It’s important to wash them away so your skin can focus on its important nightly functions.

Make sure you moisturize. Most moisturizers work better at night when you’re not diluting them with makeup or sunscreen. Night moisturizers loaded with antioxidants are great for replenishing the skin’s supply of free radical fighters, which are depleted during the day, and retinoid creams are photosensitive, so they’re also best when used at night.